This is a revised application requesting funding for Years 31-35 of an Institutional Grant to support postdoctoral research training in transfusion medicine sciences. Since the last competitive renewal in 2002, funded research at the BloodCenter of Wisconsin (BCW) has more than doubled, and faculty available to mentor fellows has increased from 11 to 17. Available research space has been roughly doubled by an addition to the Blood Research Institute completed in December, 2006. An agreement is being negotiated with the Medical College of Wisconsin (MCW) under which Blood Center physicians will take responsibility for classical hematology at the Froedtert Memorial Lutheran Hospital, the major MCW teaching facility. These developments will enhance basic research training opportunities, open new avenues for clinical/translational research and provide training grant faculty with unprecedented access to residents and fellows who have an interest in research training. Research Opportunities available to trainees cover a broad range of clinical and basic research subjects relevant to transfusion science, including Immunology, Vascular Biology/Hemostasis, Transfusion Medicine, Stem Cell Biology and Clinical Trials. The research training experience will be essentially full time. Trainees will be expected to gain a basic understanding of the disciplines in which they undertake their investigations, become familiar with a variety of research methodologies, strengthen their grasp of basic science by taking selected courses in the graduate studies program of MCW and develop the ability to conduct independent research. Time spent in fellowship training is regarded as one of several stages of professional development. Accordingly additional tracks will be offered to selected trainees, including the opportunity 1) to apply for a Clinical Investigator Development Award (KO8) for continued mentoring, to apply for independent grant support, and 3) for those oriented toward a career in transfusion medicine, an opportunity for further training as a junior member of The BloodCenters medical staff. Ultimately, trainees are expected to pursue academic careers in transfusion science or a closely related discipline such as immunohematology, transplantation immunology, vascular biology, hemostasis/thrombosis or stem cell biology.